Mr. Conner
There is no reason not to use the action however you see fit. As was pointed out, even a restoration to original would still be a "parts" gun and of no more market value than any other configuration you might choose to build it into.
In addition, the original carbines had 15.5" barrels. In that they were all made before '98 they have the curious distinction of not being a firearm under Federal law, but are classified as a "destructive weapon" or some such nonsense and require special licensing and government permission to own.
The bottom line is that you cannot legally restore it to its original configuration. Methinks you have a genuine "guilt free" action and can do with it as you please.
Glenn
